fixed onclick binding

frontend/index.html

@@ -25,11 +25,11 @@
   </div>
 
   <div class="container">
-    <button id="update" class="btn btn-primary">Get data</button>
+    <button id="update" onclick="updateData()" class="btn btn-primary">Get data</button>
     <button id="download" class="btn btn-primary">Download</button>
     <button id="debug" class="btn btn-danger">DEBUG</button>
   </div>
-  
+
   <div class="container">
     <div class="row">
     <div class="col-sm">